Puffed oats and method of making same



Patented Sept. 22, 1953 PUFFED OATS AND METHOD OF MAKING SAME John M. Baer, Chicago,Ill., assignor to Guardite Corporation, a corporation of Delaware No Drawing. Application June 12, 1953, Serial No. 361,414

Claims. I.

This invention relates to a puffed cereal and method of preparing same, and particularly to puffed oats.

The present application is a continuation-inpart of my copending application, Serial No. 296,963, filed July 2, 1952, now abandoned, which in turn is a continuation-in-part of my applications, Serial No. 40,630, filed July 24, 1948, now abandoned, and copending Serial No. 189,679, filed October 11, 1950, now abandoned. My application, Serial No. 189,679, filed October 11, 1950, was a continuation-in-part of my following applications: Serial No. 34,821, now abandoned; Serial No. 34,822, now abandoned; and "Serial No. 34,823, now abandoned, all filed July 23, 1948; Serial No. 23,869, filed April 28, 1948, now abandoned; Serial No. 38,179, filed July 10, 1948, now abandoned; and Serial No. 40,630, filed July 24, 1948, now abandoned.

Reference is had to the related cases of John M. Baer and Frank B. Doyle, Serial No. 62,984, filed December 1, 1948; Allison and Carman, Serial No. 161,744, filed May 12, 1950, now abandoned; Carman and Allison, Serial No. 259,313, filed November 30, 1951, now abandoned; and Carman and Allison, Serial No. 275,458, filed March 7, 1952, now abandoned.

The problem of pufiing organic cellular material such as oats involves a large number of interlocking variables. The oat cells are such as will trap expanding gas and thus provide the pressure differential necessary for pufiing. A sudden drop in pressure must be provided of such amount to produce the pressure difference necessary not only to expand the cell walls but to do so in spite of the leakage that necessarily occurs. On the other hand, the pressure difference must be great enough to exceed the elastic limit of-the material before pufi'ing has occurred. The expansability of the'cell wall normally depends upon the moisture content of the product, the condition of that moisture as to being free or combined, the temperature of the article and'its chemical condition, particularly as to whether it is cooked or uncooked. n r

Likewise, there must not only be the pressure dilference required to institute pufling, but there must be a volumetric increase of the gases involved sufiicient to maintain it.

I have now found that another factor involved, which has hitherto been completely overlooked, but the accomplishment of which is inherent in the operation described in my previous applicamoved. One of the difiiculties encountered in many instances of pufiing in the prior art was that the oats could be pufied, but after pufiing would collapse because of the weakened condition of the walls following the leakage out of the gas which produced pufling. This was particularly true if, after pufling, the pressure out- 7 side of the pulled oats was increased.

I have now found that by suddenly cooling and dehydrating the product so that its final temperature is below 150 F. and preferably well below 100 F.--as for example, from 32 F. or lower up to, say 100 F., that the cell walls of the product on puffing are cold set so that on standing or on the application of pressure, even of a greatly increased amount, collapse does not occur.

These results are obtained automatically by following the procedures already outlined in my previous applications. In these procedures, the following points are important:

1. Substantially all of the air should be removed from the product and replaced by an atmosphere of steam prior to pufiing.

2. The product should be cooked or moistened by steam or otherwise, preferably by the addition of substantially air-free steam at higher pressure and temperatures until the condition of the material is properfor pulling and its moisture content is within the desired range. The use of the process permits the introduction of substantially more moisture than was permissible under the old processes.

3. It is preferred that the sudden release of pressure be into a maintained vacuum zone which is initially below 8 inches of mercury absolute. The conditions of the resulting explosion should be such as to cause cold setting of the puffed oats. This means that in actual practice, employing commercially practicable vacuum equipment, the pressure may ride up somewhat during the pufiing step. It is preferred to continue evacuation of the vacuum zone during the pufiing step so as to cause cold setting of the puffed oats. The expansion of air-free steam into a vacuum of 4 inches of mercury absolute will automatically reduce the temperature of the product to approximately 125 F. Reduction of the pressure to 2 inches reduces the temperature tions referred to, is that once the oats have been puffed, the puffed condition must be maintained even after the pressure diiference has been reapproximately to 100 F. Reduction to 1 inch reduces it to about 79 F. and reduction to 0.2 inch reduces it to approximately 34 F.

Furthermore, by puffing into a maintained vacuum, it is possible to obtain a greater temperature drop in number of degrees between the maximum and minimum than was ordinarily obtainable heretofore. The result of this greater temperature drop was to permit the evaporation of more water from the product by boiling into steam. This boiling not only maintained the pressure diiference for pulling, but the removal of the water helped to cold set the cell walls by reducing plasticity and elasticity. The combination of the moisture reduction plus chilling, particularly below 100 F., has produced results not heretofore obtainable.

In a vacuum process, this reduction of temperature is of particular significance, since the lower the vacuum used the greater is the increase in pressure after the completion of the puffing operation when the material is taken back into the atmosphere. If it were not for the cooling and drying eifects, many products would not be able to maintain their puffing condition when the pressure is increased, for example from 2 inches absolute to 30 inches absolutean increase of fifteenfold.

The removal of the air from inside the oat grains in the first instance has a number of advantages. In the first place, the oxygen of the air has a deleterious effect on the oat grains, particularly when they are heated. Secondly, the removal of non-condensable gases increases the permeability of the oat grains to heat and to steam so that heating will occur uniformly and the steam will penetrate equally to all portions of the oat grains.

Thus, when it comes to introducing steam for increasing the moisture content of the product and for cooking it to the necessary chemical and physical conditions, the fact that air is not pres ent inside the oat grains produces a rapidity and uniformity of steaming and cooking not otherwise possible. Because of this greater uniformity and speed, it is possible to go to higher temperatures and pressures than would otherwise be possible. Normally, however, it permits the use of lower temperatures and pressures than otherwise required.

The Doyle patent, No. 2,627,221 which issued February 3, 1953, shows a puffing apparatus particularly suitable for carrying out the processes herein described. In such an apparatus a steaming chamber is provided within which the product may be placed. This steaming chamber is connected by a triggered door to an expansion chamber. The expansion chamber is preferably kept at a very low pressure, means being provided to maintain a low pressure during the puffing. The steaming chamber is provided with evacuating means, steaming means, and usually with a purge line through which non-condensable gases can be eliminated as well as some condensed steam which is developed during steaming.

As an example of the process, oats were introduced to the steaming chamber. Air and other non-condensable gases were removed from the cat grains by reducing the pressure in the steamll'lg chamber to about 0.2 inch of mercury absolute while withdrawing the generated steam, the cats being at a temperature of not less than about 40 F. Saturated steam was then introduced and the pressure increased to 100 pounds per square inch gauge, held there for 6 minutes, following which the oats were fired into the expansion chamber, which in this instance was at a pressure of 0.2 inch of mercury absolute. This firing is done by suddenly releasing the triggered door of the expansion chamber and the resulting explosion ejects the oats into the expansion chamber.

The actual values of the variables in the cooking-puffing cycles of this method depend upon the condition and type of oats being used, as well as the degree of pufiing desired.

The oat grains in their normal dry state may be employed without moistening. However, in some instances, it may be desired to supply flavor, and/or moistening, and/or nutritional values to the grain, prior to, during, or after puffing. This may be done by the use of a liquid carrier, such as water, under high temperature and pressure which is exploded into the vessel maintaining the product under high vacuum in an atmosphere of steam. By using water under a pressure and temperature corresponding to that, of say, 100 pounds gauge of steam, the particles may be exploded into a fine mist which will penetrate the grains, particularly after they have been puifed. In this way moisture, sugar, salt, certain vitamins, and nutritional salts may be supplied to the material with or without other flavoring agents. This may be done immediately following the initial evacuation (i. .e., during cooking) or immediately following the pufiing. It is less economical to do it at some intermediate stage.

The oats should be thoroughly cooked for desirable puffing. I have found that cooking at from 50 to 100 pounds steam pressure gauge for a period of from about 4 to 18 minutes produces satisfactory results. Following cooking, the steam pressure was adjusted to from '75 to 100 pounds gauge, after which the pressure was then immediately reduced to sub-atmospheric, preferably below 8 inches of mercury absolute and particularly to about 0.2 inch of mercury absolute. This was done by opening the triggered door of the puiiing apparatus and firing the cats into the expansion chamber. The pressure within the expansion chamber was maintained at a low point b continuing the evacuation during the putting and normally the pressure in that chamber was not permitted to exceed 4 inches of mercury absolute and preferably not permitted to exceed 2 inches of mercury absolute. In some instances, however, I have operated successfully with the pressure in the expansion chamber following the explosion riding up to as high as 4 to 8 inches of mercury absolute as measured on a standard mercury manometer, but "in most instances the pressure was reduced below 4 inches of mercury absolute within a few minutes and before reimposition of atmospheric pressure.

The resulting vacuum puffed cats have a volume of from about 4 to 8 times the original grains as determined by their cup weights. Put conversely, the specific gravity as determined by cup weights is about 12 /2'% to 25% of the specific gravity of the original oat grains. The vacuum puffed oat grains are everted, substantially pure white except for the bran particles adhering thereto, and are entirely difierent in shape from the original oat grains. The cellular structure is vitreous in appearance and the product is immediately wettable by water except for those portions protected by the bran fragments which adhere to the puifed oat particle.

The vacuum puffed oats, puffed according to the method of this invention, may be stored for long periods of time under atmospheric cond tions without becoming rancid. Samples have been stored in containers for periods of from 3 to 6 months under atmospheric conditions without turning rancid.

Examples of applying the method of this invention are:

Example 1 Hulled oats (10 pounds) were placed in the steam chamber and the pressure reduced to about 0.2 inch of mercury absolute for 2 minutes, the oats being at a temperature not less than about 40 F., to remove substantially all of th noncondensable gases. The oats were then steamed to a pressure of 100 pounds per square inch gauge, held there for 6 minutes accompanied by continual purging of the steam, and then fired into the expansion chamber which was at a pressure of 0.2 inch of mercury absolute. Evacuation of the expansion chamber was continued during th puff until the oat grainswere cold set.

Example 2 Hulled cats (10 pounds) were treated in the same manner as in Example 1, except that in the steaming and pufilng cycles, the oats were steamed to 50 pounds per square inch gauge, held there for 15 minutes, steamed quickly to 100' pounds per square inch gauge, held there for 2 minutes, and then fired, into the expansion chamber.

Example 3 Hulled cats (10 pounds) were treated in the same manner as in Example 1, except that in the steaming and puffing cycles, the cats were steamed to 60 pounds per square inch gauge, held there for 15 minutes, quickly steamed to 190 pounds per square inch gauge, held there for 3 minutes, and then fired into the expansion chamber.

Erampled Hulled cats (10 pounds) were treated in the same manner as in Example 1, except that in the steaming cycle the oats were steamed to a pressure of 100 pounds per square-inch gauge and held there for 8 minutes instead of 6 minutes.

Example 5 T Hulled oats (35 pounds) weretreated in the same manner as in Example 1, except that in the steaming cycle the cats were steamed to a pressure of 100 pounds per square inch gauge and held there for 4 minutes instead of 6 minutes.

Example 6 Hulled oats pounds) were treated in the same manner as in Example 1, except that in the steaming cycle the oats were steamed to a pressure of 160 pounds per square inch gauge and held there for 10 minutes instead of 6 minutes.

Example 7 Hulled cats (10 pounds) were treated in the same manner as in Example 1, except that in the steaming and pufiing cycles the oats were steamed to a pressure of 100 pounds per square inch gauge, held there for 6 minutes accompanied by continual purging of the steam, and then fired 6 into the expansion chamber which was at a pres' sure of 0.2 inch of mercury absolute.

Example 9 Example 10 Hulled cats (10 pounds) were treated in the same manner as Example 1, except that in the steaming and puffing cycles the oats were steamed to a pressure of 55 pounds per square inch gauge in 15 minutes, quickly steamed to pounds gauge, held there for 1 minute, and then fired into the expansion chamber which was at a pressure of about 0.2 inch of mercury absolute.

Example 11 Hulled oats (10 pounds) were treated in the same manner as Example 10, except that in the steaming and pufiing cycles the oats were subjected to a pressure of 100 pounds per square inch 7 gauge for 6 minutes instead of 1 minute, and

then fired into the expansion chamber which was at a pressure of about 0.2 inch of mercury absolute.

The vacuum puffed oats from Examples 1 to 11 were 'very satisfactory having the above described some purposes a slight case hardening and toasting are suitable and may be desirable. The case hardening markedly slows down absorption of aqueous liquids.

Puifed oats are not commercially available and therefore no comparisons can be made. However, a puffed oat prepared by the present process by freeing from air, steaming at 55 pounds gauge for 15 minutes, raising to 100 pounds gauge, holding there for 1 minute, and then pufiing to a substantial vacuum showed 62% lysine retention.

Another vacuum puifed oat product similarly prepared except that it was held at 100 pounds gauge for 6 minutes showed 65% lysine retention.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, for some modifications will be obvious to those skilled in the art.

I claim:

1. The method of puffing oats which comprises: freeing oat grains from air and replacing the air with an atmosphere of steam, cooking the oat grains for a period suflicient to soften the cell walls and adapt them for pufiing, then subjecting the oat grains to a sudden change from a high super-atmospheric pressure to a low subatmospheric pressure whereby they are puffed.

2. The method as set forth in claim 1 in which aczsspse the cat grains are cooked under a. pressure of steam of approximately 50. to 1.00 pounds per square inch gauge.

3. The method asset forth in claim 1 in which the cat grains are cooked under a pressure of steam of. approximately 50 to 1.00 pounds per square inch gauge, the pressure adjusted to from '75 to 100 pounds per square inch gauge, and then instantaneously reducing the pressure by shooting the oat grains into a low sub-atmospheric pressure whereby they are puffed.

4. Themethod as set forth in claim 1 in which the oats are cooked for a period of from 4 to 18 minutes at a pressure of from 50 to 100 pounds per square inch gauge.

5. The method which comprises cooking cats in an atmosphere of, steam, suddenly reducing the pressure below 8 inches of mercury absolute to puff the oats, and then drying the puffed oats under the sub-atmospheric pressure.

6. The method as set forth in claim 5 in which the drying is accomplished while supplying heat to the cats.

7. The method which comprises pufiing oats by a sudden reduction in pressure in an atmosphere of steam and concluding the operation at an absolute pressure substantially below 8 inches of mercury absolute, and then introducing a volatile liquid at a temperature sufiiciently high to have an internal vapor pressure markedly above atmospheric, said mist containing additive flavoring or nutritive ingredients, whereby the liquid explodes into a fine mist and penetrates the cats.

8. In the puffing of oats, the steps of heating the oats in the presence of moisture to produce a, superatmospheric steam pressure thereon and then puffing the product into a maintained vacuum sufiiciently low to cold set the product by evaporation of moisture from and consequent cooling of the product and reimposing atmospheric pressure upon the product while in cold set condition.

9. The process of claim 8 in which the puffing operation is carried out as a batch process, the

pufiing being into a vacuum, which is initially at substantially absolute zero pressure and which rises during the pufiing operation to, a point not above an average pressure of 4 inches of' mercury absolute.

10. The process of claim 8 in which the pufling operation is carried out as ahatch process, the puffingbeing into a vacuum which is initially at substantially absolute zero pressure and which rises during the puffing operation to a point not above-an average pressure of 2' inches of mercury absolute.

11 The method of claim 8 in which the product is dried after the pufling operation is complete but before reimposition of atmospheric pressure.

12. The method of claim 8 in which the temperature of the product is reduced below F. before reimposition of atmospheric pressure.

13. The method of claim 8 inwhich the temperature of the product is reduced below 50 F. before reimposition of atmospheric pressure.

14. The method of claim 8 in which the temperature of the product is reduced below F. before reimposition of atmospheric pressure.

15. A cold set, vacuum puffed, oat product produced. by the. process set forth in claim 8.

JOHN M. BAER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,933,158 Bohn et a1 Oct. 31, 1933 2,246,528 Musher June 24, 1941 2,261,456 Warren Nov. 4, 1941 2,278,464 Musher Apr. 7, 1942 2,295,116 Kellogg Sept. 18, 1942 2,358,250 Rogers Sept. 12, 1944 2,438,939 Ozai-Durrani Apr. 6, 1948 FOREIGN PATENTS Number Country Date 494,085 Great Britain of 1931 

1. THE METHOD OF PUFFING OATS WHICH COMPRISES: FREEING OAT GRAINS FROM AIR AND REPLACING THE AIR WITH AN ATMOSPHERE OF STEAM, COOKING THE OAT GRAINS FOR A PERIOD SUFFICIENT TO SOFTEN THE CELL WALLS AND ADAPT THEM FOR PUFFING, THEN SUBJECTING THE OAT GRAINS TO A SUDDEN CHANGE FROM A HIGH SUPER-ATMOSPHERIC PRESSURE TO A LOW SUBATMOSPHERIC PRESSURE WHEREBY THEY ARE PUFFED. 